Cushioning elements play a great role in the field of sports apparel and are used for clothing for the most varied types of sports. Exemplarily, winter sports clothing, running wear, outdoor clothing, football wear, golf clothing, martial arts apparel or the like may be named here. Generally, cushioning elements serve to protect the wearer from shocks or blows, and for padding, for example, in case the wearer falls down. For this, the cushioning elements typically comprise one or more deformation elements that deform under an external effect of pressure or a shock impact and thereby absorb the impact energy.
A particularly important role is to be attributed to the cushioning elements in the construction of shoes, especially sports shoes. By means of cushioning elements in the form of soles, shoes are provided with a large number of different properties which may vary considerably, according to the specific type of the shoe. Primarily, shoe soles have a protective function. By their stiffness, which is higher than that of the shoe shaft, they protect the foot of the respective wearer against injuries caused, e.g., by pointed or sharp objects that the wearer of the shoe may step on. Furthermore, the shoe sole, due to its increased abrasion resistance, usually protects the shoe against excessive wear. In addition, shoe soles may improve the contact of the shoe on the respective ground and thereby enable faster movements. A further function of a shoe sole may comprise providing certain stability. Moreover, a shoe sole may have a cushioning effect in order to, e.g., cushion the effects produced by the contact of the shoe with the ground. Finally, a shoe sole may protect the foot from dirt or spray water and/or provide a large variety of other functionalities.
In order to accommodate the large number of functionalities, different materials are known from the prior art which may be used for manufacturing cushioning elements for sports apparel.
Exemplarily, reference is made here to cushioning elements made of ethylene-vinyl-acetate (EVA), thermoplastic polyurethane (TPU), rubber, polypropylene (PP) or polystyrene (PS), in the form of shoe soles. Each of these different materials provides a particular combination of different properties that are more or less well suited for soles of specific shoe types, depending on the specific requirements of the respective shoe type. For instance, TPU is very abrasion-resistant and tear-resistant. Furthermore, EVA distinguishes itself by having a high stability and relatively good cushioning properties. Furthermore, the use of expanded materials, in particular, of expanded thermoplastic urethane (eTPU) was taken into account for the manufacture of a shoe sole. Expanded thermoplastic urethane has a low weight and particularly good properties of elasticity and cushioning. Furthermore, according to WO 2005/066250, a sole of expanded thermoplastic urethane may be connected to a shoe shaft without additional adhesive agents.
Moreover, US 2005/0150132 A1 discloses footwear (e.g., shoes, sandals, boots, etc.) that is constructed with small beads stuffed into the footbed, so that the beads may shift about due to pressure on the footbed by the user's foot during normal use. DE 10 2011 108 744 A1 discloses a method for the manufacture of a sole or part of a sole for a shoe. WO 2007/082838 A1 discloses foams based on thermoplastic polyurethanes. US 2011/0047720 A1 discloses a method of manufacturing a sole assembly for an article of footwear. Finally, WO 2006/015440 A1 discloses a method of forming a composite material.
One disadvantage of the cushioning elements which are known from prior art, in particular of the known shoe soles, is that these have a low breathability. This disadvantage may considerably restrict the wearing comfort of the sports clothing that contains the cushioning element, since it leads to increased formation of sweat or heat accumulation under the clothing. This is disadvantageous particularly in cases where the clothing is worn continuously for a longer time, as, for instance, during a walking tour or a round of golf or during winter sports. Furthermore, cushioning elements often increase the overall weight of the sports clothing in a an amount that is not insignificant. This may have an adverse effect on the wearer's performance, in particular in sports of endurance or running.
Starting from prior art, it is therefore an object of the present invention to provide better cushioning elements for sports apparel, in particular for soles for sports shoes. A further object of the present invention comprises improving the breathability of such a cushioning element and in further reducing its weight.